CDK4 and neoplasm: Induction of apoptosis after PaRi has also been described in bladder cancer cells and T cell acute lymphoblastic leukaemia, while in pancreatic ductal adenocarcinoma cell lines, CDK4/6 inhibition alone did not induce apoptosis.41–43 Thus, induction of apoptosis in response to CDK4/6 inhibition seems to be tumour type dependent, but is in general of benefit in terms of a therapeutic application.